1. Field of the Invention
This invention pertains to an improved DC to AC inverter having an improved housing and mounting assemblies with plural diverse electrical components, providing improved thermal disipation, greater safety, and greater reliability.
2. The Prior Art
Inverter systems which convert DC to AC are of use in the motorhome, recreational vehicle (RV), farm tractor, boat, trucking, construction and other industries. The most common inverter system provides 115 volt AC power from the 12 volt DC battery system commonly found on vehicles. The inverter system is typically used to provide AC electrical power for small refrigerators, appliances, vacuum cleaners, hair dryers, televisions, radios, small AC power tools, computers, lighting systems and the like. The inverter system can replace a much costlier, larger, heavier and maintenance intensive gas engine powered generator system.
Prior art patents seem to be concentrated in:
class 307, subclasses 10, 150 and 157, and
class 363, subclasses 41, 97 and 134.
A first representative prior art patent is 4,376,250 which has a mobile inverter system on a wheeled cart with its own discrete batteries. This inverter has a chassis and construction specifically for discrete mobility. U.S. Pat. No. 4,317,165 has an improved electronic component structure providing improved efficiency and regulation of output voltage.
The big problems with inverters are heat, disipation of the heat, durability, isolation of high voltage, physical size, and liability in view of the prevailing lack of agency testing and approval.
Heat concentration and hot spots are problems. High temperature reduces the performance and shortens the life of electronic components. Persons around the inverter are presently exposed to injurious high temperatures on exterior surfaces of the inverters. Ignition of gasoline, or natural gas or LP vapors is also a problem.
Durability has been most often manifested by broken components as a consequence of the vibration and shock typically seem in over-the-road trucks and other vehicles. Component leads, components, and solder joints tend to break and/or separate.
The transformer mounts have been problems. Typically the transformer has been mounted vertically upon a sub-frame. Under impact and vibration the transformer has been one of the first things to break loose, or has bent the frame, sub-frame and/or electrical leads in the inverter.
The physical configuration of wiring, circuitry and leads in existing inverters is causing excess inductance and is responsible for relatively poor performance and premature component failure.
Isolation of high voltage AC from the low voltage DC is a problem because the leads and components are intermixed and crossed within the inverter component compartment.
The relatively large physical size of existing inverters is a detriment to their acceptance and usage, particularly in such space efficient devices as RVs, truck tractors and boats. A good part of the bulk and relatively large size is a consequence of using size and volume to distribute and disipate heat from the inverter, and to keep high and low voltage components separated.
Lack of agency approvals, specifically UL, CSA and others, is a problem which is a serious detriment to acceptance and usage of inverters. RV manufacturers and truck manufacturers and dealers will not assume or not be permitted to assume by their insurers the liabilities involved for the sale and installation of untested and unapproved electrical equipment that can cause fires, explosions, cause property damage and/or injure people.
Relatively high costs and selling prices from excessive componentry usage and manufacturing costs, have also been a detriment to the successful commercialization and usage of inverters.
Only one other inverter is known to be UL approved, and it is relatively enormous in size and does not lend itself to usage in space efficient structures.